'\" t
.\"     Title: passwd
.\"    Author: Julianne Frances Haugh
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 18/06/2024
.\"    Manual: User Commands
.\"    Source: shadow-utils 4.16.0
.\"  Language: French
.\"
.TH "PASSWD" "1" "18/06/2024" "shadow\-utils 4\&.16\&.0" "User Commands"
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.SH "NOM"
passwd \- Modifier le mot de passe d\*(Aqun utilisateur
.SH "SYNOPSIS"
.HP \w'\fBpasswd\fR\ 'u
\fBpasswd\fR [\fIoptions\fR] [\fILOGIN\fR]
.SH "DESCRIPTION"
.PP
The
\fBpasswd\fR
command changes passwords for user accounts\&. A normal user may only change the password for their own account, while the superuser may change the password for any account\&.
\fBpasswd\fR
also changes the account or associated password validity period\&.
.SS "Modifications du mot de passe"
.PP
Dans un premier temps, l\*(Aqutilisateur doit fournir son ancien mot de passe, s\*(Aqil en avait un\&. Ce mot de passe est ensuite chiffr\('e puis compar\('e avec le mot de passe enregistr\('e\&. L\*(Aqutilisateur n\*(Aqa droit qu\*(Aq\(`a un seul essai pour entrer le mot de passe correct\&. Le superutilisateur peut contourner cette premi\(`ere \('etape de mani\(`ere \(`a changer les mots de passe ayant \('et\('e oubli\('es\&.
.PP
After the password has been entered, password aging information is checked to see if the user is permitted to change the password at this time\&. If not,
\fBpasswd\fR
refuses to change the password and exits\&.
.PP
Le nouveau mot de passe sera demand\('e deux fois \(`a l\*(Aqutilisateur\&. Le second mot de passe est compar\('e avec le premier\&. Ces deux mots de passe devront \(^etre identiques pour que le mot de passe soit chang\('e\&.
.PP
Then, the password is tested for complexity\&.
\fBpasswd\fR
will reject any password which is not suitably complex\&. Care must be taken not to include the system default erase or kill characters\&.
.SS "Astuces pour les mots de passe"
.PP
The security of a password depends upon the strength of the encryption algorithm and the size of the key space\&. The legacy
\fIUNIX\fR
System encryption method is based on the NBS DES algorithm\&. More recent methods are now recommended (see
\fBENCRYPT_METHOD\fR)\&. The size of the key space depends upon the randomness of the password which is selected\&.
.PP
Les compromissions de la s\('ecurit\('e des mots de passe r\('esultent le plus souvent d\*(Aqune n\('egligence dans le choix du mot de passe, ou lors de son utilisation\&. Pour cette raison, vous ne devez pas s\('electionner de mot de passe apparaissant dans un dictionnaire ou devant \(^etre \('ecrit\&. Le mot de passe ne doit pas non plus \(^etre un nom propre, un num\('ero min\('eralogique, une date de naissance, ou une adresse\&. En effet ceux\-ci pourraient \(^etre devin\('es pour violer la s\('ecurit\('e du syst\(`eme\&.
.PP
As a general guideline, passwords should be long and random\&. It\*(Aqs fine to use simple character sets, such as passwords consisting only of lowercase letters, if that helps memorizing longer passwords\&. For a password consisting only of lowercase English letters randomly chosen, and a length of 32, there are 26^32 (approximately 2^150) different possible combinations\&. Being an exponential equation, it\*(Aqs apparent that the exponent (the length) is more important than the base (the size of the character set)\&.
.PP
Vous pouvez trouver des conseils sur la fa\(,con de choisir un mot de passe robuste sur http://en\&.wikipedia\&.org/wiki/Password_strength (en anglais)\&.
.SH "OPTIONS"
.PP
The options which apply to the
\fBpasswd\fR
command are:
.PP
\fB\-a\fR, \fB\-\-all\fR
.RS 4
This option can be used only with
\fB\-S\fR
and causes show status for all users\&.
.RE
.PP
\fB\-d\fR, \fB\-\-delete\fR
.RS 4
Supprimer le mot de passe (le rendre vide) d\*(Aqun utilisateur\&. C\*(Aqest une fa\(,con rapide de supprimer l\*(Aqauthentification par mot de passe pour un compte\&. Il rend le compte indiqu\('e sans mot de passe\&.
.RE
.PP
\fB\-e\fR, \fB\-\-expire\fR
.RS 4
Annuler imm\('ediatement la validit\('e du mot de passe d\*(Aqun compte\&. Ceci permet d\*(Aqobliger un utilisateur \(`a changer son mot de passe lors de sa prochaine connexion\&.
.RE
.PP
\fB\-h\fR, \fB\-\-help\fR
.RS 4
Afficher un message d\*(Aqaide et quitter\&.
.RE
.PP
\fB\-i\fR, \fB\-\-inactive\fR\ \&\fIINACTIVE\fR
.RS 4
This option is used to disable an account after the password has been expired for a number of days\&. After a user account has had an expired password for
\fIINACTIVE\fR
days, the user may no longer sign on to the account\&.
.RE
.PP
\fB\-k\fR, \fB\-\-keep\-tokens\fR
.RS 4
Indiquer que la modification de mot de passe ne sera effectu\('ee que lors de l\*(Aqexpiration des jetons d\*(Aqauthentification (mots de passe)\&. C\*(Aqest utile dans le cas o\(`u l\*(Aqutilisateur voudrait conserver ses jetons d\*(Aqauthentification encore valables\&.
.RE
.PP
\fB\-l\fR, \fB\-\-lock\fR
.RS 4
Verrouiller le mot de passe du compte indiqu\('e\&. Cette option d\('esactive un mot de passe en le modifiant par une valeur qui ne correspond pas \(`a un mot de passe chiffr\('e possible (cela ajoute un \(Fo\ \&!\ \&\(Fc au d\('ebut du mot de passe)\&.
.sp
Note that this does not disable the account\&. The user may still be able to login using another authentication token (e\&.g\&. an SSH key)\&. To disable the account, administrators should use
\fBusermod \-\-expiredate 1\fR
(this set the account\*(Aqs expire date to Jan 2, 1970)\&.
.sp
Les utilisateurs avec un mot de passe verrouill\('e ne sont pas autoris\('es \(`a le changer\&.
.RE
.PP
\fB\-n\fR, \fB\-\-mindays\fR\ \&\fIMIN_DAYS\fR
.RS 4
Set the minimum number of days between password changes to
\fIMIN_DAYS\fR\&. A value of zero for this field indicates that the user may change their password at any time\&.
.RE
.PP
\fB\-q\fR, \fB\-\-quiet\fR
.RS 4
Mode silencieux\&.
.RE
.PP
\fB\-r\fR, \fB\-\-repository\fR\ \&\fIREPOSITORY\fR
.RS 4
change password in
\fIREPOSITORY\fR
repository
.RE
.PP
\fB\-R\fR, \fB\-\-root\fR\ \&\fICHROOT_DIR\fR
.RS 4
Apply changes in the
\fICHROOT_DIR\fR
directory and use the configuration files from the
\fICHROOT_DIR\fR
directory\&. Only absolute paths are supported\&.
.RE
.PP
\fB\-P\fR, \fB\-\-prefix\fR\ \&\fIPREFIX_DIR\fR
.RS 4
Apply changes to configuration files under the root filesystem found under the directory
\fIPREFIX_DIR\fR\&. This option does not chroot and is intended for preparing a cross\-compilation target\&. Some limitations: NIS and LDAP users/groups are not verified\&. PAM authentication is using the host files\&. No SELINUX support\&.
.RE
.PP
\fB\-S\fR, \fB\-\-status\fR
.RS 4
Afficher l\*(Aq\('etat d\*(Aqun compte\&. Cet \('etat est constitu\('e de 7 champs\&. Le premier champ est le nom du compte\&. Le second champ indique si le mot de passe est bloqu\('e (L), n\*(Aqa pas de mot de passe (NP) ou a un mot de passe utilisable (P)\&. Le troisi\(`eme champ donne la date de derni\(`ere modification du mot de passe\&. Les quatre champs suivants sont\ \&: la dur\('ee minimum avant modification, la dur\('ee maximum de validit\('e, la dur\('ee d\*(Aqavertissement, et la dur\('ee d\*(Aqinactivit\('e autoris\('ee pour le mot de passe\&. Les dur\('ees sont exprim\('ees en jours\&.
.RE
.PP
\fB\-u\fR, \fB\-\-unlock\fR
.RS 4
Unlock the password of the named account\&. This option re\-enables a password by changing the password back to its previous value (to the value before using the
\fB\-l\fR
option)\&.
.RE
.PP
\fB\-w\fR, \fB\-\-warndays\fR\ \&\fIWARN_DAYS\fR
.RS 4
Set the number of days of warning before a password change is required\&. The
\fIWARN_DAYS\fR
option is the number of days prior to the password expiring that a user will be warned that their password is about to expire\&.
.RE
.PP
\fB\-x\fR, \fB\-\-maxdays\fR\ \&\fIMAX_DAYS\fR
.RS 4
Set the maximum number of days a password remains valid\&. After
\fIMAX_DAYS\fR, the password is required to be changed\&.
.sp
Passing the number
\fI\-1\fR
as
\fIMAX_DAYS\fR
will remove checking a password\*(Aqs validity\&.
.RE
.PP
\fB\-s\fR, \fB\-\-stdin\fR
.RS 4
This option is used to indicate that passwd should read the new password from standard input, which can be a pipe\&.
.RE
.SH "AVERTISSEMENTS"
.PP
La v\('erification de la complexit\('e des mots de passe peut varier d\*(Aqun site \(`a l\*(Aqautre\&. Il est vivement conseill\('e aux utilisateurs de choisir un mot de passe aussi complexe que possible dans la limite de ce qu\*(Aqil est capable de m\('emoriser\&.
.PP
Il se peut que les utilisateurs ne puissent pas changer leur mot de passe sur un syst\(`eme si NIS est activ\('e et qu\*(Aqils ne sont pas connect\('es au serveur NIS\&.
.SH "CONFIGURATION"
.PP
The following configuration variables in
/etc/login\&.defs
change the behavior of this tool:
.SH "FICHIERS"
.PP
/etc/passwd
.RS 4
Informations sur les comptes des utilisateurs\&.
.RE
.PP
/etc/shadow
.RS 4
Informations s\('ecuris\('ees sur les comptes utilisateurs\&.
.RE
.PP
/etc/login\&.defs
.RS 4
Configuration de la suite des mots de passe cach\('es \(Fo\ \&shadow password\ \&\(Fc\&.
.RE
.SH "VALEURS DE RETOUR"
.PP
The
\fBpasswd\fR
command exits with the following values:
.PP
\fI0\fR
.RS 4
success
.RE
.PP
\fI1\fR
.RS 4
permission denied
.RE
.PP
\fI2\fR
.RS 4
invalid combination of options
.RE
.PP
\fI3\fR
.RS 4
unexpected failure, nothing done
.RE
.PP
\fI4\fR
.RS 4
unexpected failure,
passwd
file missing
.RE
.PP
\fI5\fR
.RS 4
passwd
file busy, try again
.RE
.PP
\fI6\fR
.RS 4
invalid argument to option
.RE
.SH "VOIR AUSSI"
.PP
\fBchpasswd\fR(8),
\fBmakepasswd\fR(1),
\fBpasswd\fR(5),
\fBshadow\fR(5),
\fBlogin.defs\fR(5),
\fBusermod\fR(8)\&.
.PP
The following web page comically (yet correctly) compares the strength of two different methods for choosing a password: "https://xkcd\&.com/936/"
